Transform Your Mopar 440 Into A 512-inch Monster

Not too long ago, the dream of building a 500ci Mopar big-block wedge only came true for professional drag racers and rich street rats who could afford the steep price tag of billet steel cranks, billet rods, and custom-machined pistons—all of which could easily top the $5,000 mark.

The rest of us were forced to cobble our Mopar big-block stroker combinations together by stuffing welded-up 440 cranks and big-block Chevy connecting rods into low-deck (B series) 400 blocks to get 496 cubes. The resulting rotating assembly was hardly a drop-in proposition and required plenty of block-grinding and expensive Mallory metal for balancing. Worse, the 400 block’s shorter 9.980-inch deck height brought the heads too close together, preventing the use of more bountiful 440 intake manifolds, which only fit the RB 413, 426, and 440 block’s greater 10.725-inch deck height.

Thankfully, times have changed, and for a mere $1,995, there’s a true drop-in rotating assembly available from 440 Source that’ll transform any RB-series 440 block into a killer 512ci street and strip killer. The only exotic effort involves boring the block 0.055 inch oversize. If it weren’t for the cylinder boring, you could realistically install this kit in a weekend. Imagine pulling your Mopar 440 into the garage on Friday night and emerging Monday morning with a 512-cube torque machine. Our test subject, a mild 334hp, 358-lb-ft, cast-gut Mopar 440 grew into a 409hp, 411-lb-ft stormer after the stroker swap and cam upgrade. Plus, it revs like a small-block now.

There’s more—440 Source offers no less than sixty-one 400 (B series) and 440 (RB series) big-block–based stroker kits that’ll deliver up to 543 reliable cubic inches with compression ratios to suit any need. Every one of these kits consists of brand-new parts and is kept in stock for immediate shipment and instant gratification for all parties involved. Let’s watch as Donald Wood and the guys at R.A.D. Auto Machine in Ludlow, Massachusetts, explore the 440 Source 512 stroker kit and see what it has to offer.